In motor vehicle occupant protection systems, airbags are being increasingly used which have two gas generators which are each equipped with their own firing stage. In this way, the inflation of the airbag can be adapted better to the respective requirements. If the second inflation stage is not required to protect the persons to be protected when there is an accident or if its firing even constitutes a hazard, it is possible for the second stage not to be fired directly after the first stage. However, so that helpers or rescue service personnel are not put in danger as a result of the second stage firing, it is expedient to fire the second stage automatically after the first stage, but at a time at which the person to be protected is no longer placed in danger. For it to be at all possible to fire a firing stage, a safety switch must be closed. Such a safety switch generally closes even when there are decelerations below a threshold value at which it is necessary to inflate the airbag.
If, as in the case described above, firing the second firing stage takes place with a long delay with respect to that of the first firing stage, the safety switch is opened again so that it is no longer possible to fire the second stage.